17 year old on illegal website

I didn't actually know this website was illegal until a friend told me. My son loves anime. His entire room is anime. He watches a lot of anime and when he's on his Xbox I see him watch anime on a website called kiss anime. One of my friends told me kiss anime is an illegal website with pirated anime. I freaked out and yelled at him for watching illegal anime in my house but my boyfriend said I'm completely overreacting and kiss anime has been around for a long time and not a single person has ever gone to jail for watching kiss anime. I said"Well it's illegal." He said "It's not child porn. No one is gonna bust down your door for watching stuff on kiss anime. Chill." I don't know a whole lot about these websites and stuff but am I overreacting?